The versatility of the reactive polyamide resins as hardeners for the solid, liquid, and modified epoxies which contain epoxy or oxirane rings on terminal positions is well known. However, to protect corrosion-susceptible metal substrates such as those of the aluminum and ferrous alloys, corrosion inhibitors must be added to the hardener/epoxy mixture, particularly when exposure to humid and saline atmospheres is involved; this presents practical problems and limitations to the usefulness of the conventional polyamide/epoxy system by requiring grind of the pigment for incorporation in the epoxy as a vehicle, its concomitant settling and phase separation because of the wide differences in specific gravity between it and the resin vehicle, and the general lack of applicability as a faying surface adhesive and sealant in the weld-bonding of structural elements.
It is an object of this invention to retain or improve the characteristics of the reactive polyamide/epoxy products while circumventing the requirement of adding pigments for corrosion protection to corrosion-susceptible metal substrates.